Automator: Get current path of automator app

I am trying to create an Automator application which I will be distributing to other users on the network. The automator app will be accompanied by a ZIP file and a PKG installer file.

I need to run the PKG installer file the automator app. For this I'm trying to use the Run Shell Script using the following command:

open gdata.pkg

The problem I'm having is that Automator cannot find this file. I think it doesn't pick up the current path. I tried changing it to following ways:

Experiment #1

cd $@; open gdata.pkg

Experiment #2

open ./gdata.pkg

Both didn't work for me. Automator keeps giving error that it couldn't run the script. How do I accomplish this here? Can anyone help.

My next step after this would be to decompress the accompanied ZIP file onto a new folder on user's desktop.

Regards F.Azhar